CHE101 Exam 1A S2018 Key PDF

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A Name Signature Recitation Instructor Recitation Day/Time

Chemistry 101 - Exam 1 Friday, March 2, 2018 Turn in all pages of your exam which consists of five pages and a periodic table. Part I should be answered on the appropriate pages in the examination. Answers to Part II should be placed on this cover sheet. For Part I, the work must be shown - the answer alone is worth very little. Part II Answers a

b

c

d

e

1. 2. 3. 4. 5. 6.

SCORE Part I 1. __________ 2.

(25 points) M1V1=M2V2

(15 points)

__________

7. 8. 9. 10. 11. 12.

Part II (5 points each) TOTAL

__________

__________

2 Name__________________________________

Part I 1.

(25 points) Answer the following questions based on the balanced chemical equation below. P4 (s) + 6 Cl2 (g)  4 PCl3 (l) A. (12 points) If 45.15 g of P 4 (molar mass: 123.9 g/mol) is mixed with 131.5 g Cl2 (molar mass: 70.91 g/mol) in a reactor, how many grams of PCl3 (molar mass: 137.33 g/mol) can be produced from this reaction?

B. (7 points) How many grams of the excess reactant will remain in the reactor?

C. (6 points) If the actual yield of PCl3 was 101.2 g, what is the % yield of this reaction?

3 Name__________________________________ 2. (15 points) 24.52 mL of 0.123 M NaOH was added to neutralize 25.00 mL of H2SO4 solution. Answer the following questions.

A. (4 points) Write equation for the neutralization reaction of H 2SO4 with NaOH and balance the equation.

B. (8 points) Using the reaction quantities and your balanced chemical equation above, what is the molarity (M) of the H2SO4 solution?

C. (3 points) Write the net ionic equation for the neutralization reaction (show your work).

4 Name__________________________________ Part II – place answers on cover sheet (5 points each)

1.

What is the correct answer (using the rules for “significant figures”) to the expression: (18 + 95) x (0.077351)? a) 8.7

2.

b) 8.74

c) 8.741

d) 8.7406

e) 8.74066

Which atom or ion has the smallest number of electrons? a) N3b) C c) Ne d) Be2+

e) Li

In which of the following name-formula pairs do both items refer correctly to the same substance? Name Formula a) Potassium Nitrate PNO3 b) Titanium (II) oxide TiO2 c) Zirconium (IV) sulfide ZrO2 d) Dichloride hexoxide Cl2O6 e) Iron (III) sulfide Fe3S 3.

4.

The number of moles of hydrogen atoms in 1.0g of glucose, C6H12O6, is a) 0.067

5.

b) 0.13

e) 0.083

b) C16H10N4O2

c) C10HN6O3

d) C4H5N2O

e) CHNO

It is found that 1.00g of sulfur reacts with 1.00g of oxygen to form 2.00g of compound. The empirical formula for the compound is a) S2O

7.

d) 12

Caffeine contains 49.5% C, 5.15% H, 28.9% N and 16.5% O. What is the empirical formula of caffeine? a) C8H5N2O

6.

c) 0.0056

b) SO

c) S2O3

b S3O2

e) SO2

In the balanced equation for w Al4C3(s)

+ x H2O (ℓ)

→

y Al(OH)3(s)

+ z CH4(g)

the coefficients w, x, y and z are a)

w = 1, x = 3, y = 4 and z = 3b) w = 2, x = 23, y = 8 and z = 6

c)

w = 2, x = 12, y = 8 and z = 8d) w = 1, x = 6, y = 4 and z = 3

e)

w = 1, x = 12, y = 4 and z = 3

5 Name__________________________________ 8.

What is the mass percentage of oxygen in calcium hydroxide, Ca(OH)2? a) 54.1% b) 43.2% c) 21.6%. d) 28.0%. e) 27.2%

9.

In the reaction of 2.00 mole carbon (C) with 6.00 mole oxygen (O2) to give CO2, if the actual yield is 30.0g, what is the percent yield? a)

10.

68.2%

d) 90.2%

e) 22.7%

b) 59.2L

c) 33.8mL

d) 16.9mL

e) 25.0mL

How many mL of a 0.33M solution of H2SO4 are required to neutralize 10.0 mL of 1.00M KOH? a) 15. mL

12.

c) 34.1%

You have a stock solution of 7.4M NH3. How many milliliters of this solution would you dilute to make 1000.0mL of 0.250 M NH3? a) 16.9L

11.

b) 17.1%

b) 20.mL

c) 10.mL

d) 60.mL

e) 80.mL

The net balanced ionic equation for reaction of Cu(OH)2(s) with HClO4(aq) is a) H+(aq) + OH-(aq) → H2O(ℓ) b) Cu2+(aq) + 2OH-(aq) + 2H+(aq) + 2ClO4-(aq) → 2H2O(ℓ) + Cu2+(aq) + 2ClO4-(aq) c) Cu(OH)2(s) + 2H+(aq) → Cu2+(aq) + 2H2O(ℓ) d) Cu(OH)2(s) + 2H+(aq) + 2ClO4-(aq) → Cu2+(aq) + 2H2O(ℓ) + 2ClO4-(aq) e) Cu2+(aq) + 2OH-(aq) + H+(aq) + ClO4-(aq) → H2O(ℓ) + Cu2+(aq) + C1O4-(aq)...